396 Tetanus 



the second class in smaller numbers, but finds the conditions 

 of growth better because of the depth of the wound. 



The severity of the wound has nothing whatever to do 

 with the occurrence of tetanus, pin -pricks, nail punctures, 

 insect stings, vaccination, and a variety of other mild 

 injuries sometimes being followed by it. 



An interesting fact has been presented by Vaillard and 

 Rouget,* who found that if the tetanus spores were intro- 

 duced into the body freed from their poison, they were 

 unable to produce the disease because of the promptness 

 with which the phagocytes took them up. If, however, 

 the toxin was not removed, or if the body-cells were injured 

 by the simultaneous introduction of lactic acid or other 

 chemic agent, the spores would immediately develop into 

 bacilli, begin to manufacture toxin, and produce the disease. 

 This suggests that many wounds may be infected by the 

 tetanus bacillus though the surrounding conditions rarely 

 enable it to develop satisfactorily and produce enough 

 toxin to cause disease. 



In very rare cases tetanus may possibly occur without 

 the previous existence of a wound, as in the case reported 

 by Kamen, who found the intestine of a person dead of 

 the disease rich in Bacillus tetani. Kamen is of the opinion 

 that the bacilli can grow in the intestine and be absorbed, 

 especially where imperfections in the mucosa exist. It is 

 not impossible, though he does not think it probable, that 

 the bacteria growing in the intestine can elaborate enough 

 toxin to produce the disease by absorption. 



A peculiar observation has been made by Montesano and 

 Montesson, * who unexpectedly found the tetanus bacillus 

 in pure culture in the cerebro-spinal fluid of a case of par- 

 alytic dementia that died without a tetanic symptom. 



Immunity. All animals are not alike susceptible to 

 tetanus. Men, horses, mice, rabbits, and guinea-pigs are 

 susceptible; dogs much less so. Cattle suffer chiefly after 

 accouchement, and after abortion. Most birds are scarcely at 

 all susceptible either to the bacilli or to their toxin. Am- 

 phibians and reptiles are immune, though it is said that frogs 

 can be made susceptible by elevation of their body-tempera- 

 ture. 



* See " Centralbl. f. Bakt., Infekt., u. Parasitenk.," vol. xvi, p. 208. 

 t"Centralbl. f. Bakt. u. Parasitenk.," Dec., 1897, Bd. xxn, Nos. 

 22, 23, p. 663. 



